Setting Method, Communication Device, and Master Device

1. A method of setting a communication parameter in a network system, comprising: a master device comprising a master processor configured with a program to perform operations comprising operation as a master storage unit, a slave out-side communication unit setting unit, and a master out-side communication unit; and a slave device comprising a slave processor configured with a program to perform operations comprising operation as a slave out-side communication unit and a slave in-side communication unit, the method comprising: storing, in response to the slave device establishing communication with a communication destination via the slave out-side communication unit, a value of the communication parameter to the master storage unit, the master device and the slave device being connected via the master out-side communication unit and the slave in-side communication unit; setting, via the slave out-side communication unit setting unit, the communication parameter to equal the stored value; and setting, in response to the communication parameter being set to equal the stored value and the slave device failing to establish communication with the communication destination via the slave out-side communication unit, the communication parameter to a value different from the stored value, via the slave out-side communication unit setting unit, wherein the communication destination is a device other than the master device or the slave device.

2. The method according to claim 1 , wherein the slave device fails to establish communication with the communication destination if the slave device and the communication destination cannot establish communication in a predetermined amount of time.

3. The method according to claim 1 , wherein the slave processor is further configured with the program to perform operations comprising operation as a slave setting unit that checks a communication setting of the communication destination and performs communication setting such that communication with the communication destination can be established, and the slave setting unit, in response to the slave device failing to establish communication with the communication destination in a predetermined amount of time, performs setting for the slave device.

4. The method according to claim 1 , wherein the communication parameter is at least one of a port type, a communication speed, and a full-duplex/half-duplex mode.

5. The method according to claim 1 , wherein the slave out-side communication unit comprises a plurality of slave out-side communication units; the stored value comprises a plurality of stored values; and the communication destination comprises a plurality of communication destinations, each connected to a different slave out-side communication unit.

6. A communication device, in a network system comprising a master device and a slave device, the communication device functioning as the master device or the slave device and setting a communication parameter relating to communication of the communication device, wherein the communication parameter is at least one of a port type, communication speed, and full-duplex/half-duplex, and a memory is provided in a device other than the communication device, the memory storing a value of the communication parameter in a state in which communication has been established with a communication destination which is a device other than the master device or the slave device; the communication device comprising: a processor coupled to the memory and configured with a program to perform operations comprising: operation as a setting unit that sets the value of the communication parameter stored in the memory.

7. A network system comprising a master device and a slave device, the master device comprising: a master processor configured with a program to perform operations comprising operation as: a master out-side communication unit; a slave out-side communication unit setting unit; a slave out-side communication unit determination unit; and a master storage unit; the slave device comprising a slave processor configured with a program to perform operations comprising operation as: a slave in-side communication unit; and a slave out-side communication unit that establishes communication with a communication destination; wherein the communication destination is a device other than the master device or the slave device; the slave out-side communication unit determination unit determines whether the slave out-side communication unit has established communication with the communication destination; the master device and the slave device are connected via the master out-side communication unit and the slave in-side communication unit; the master storage unit stores a value of a communication parameter in a state in which the slave device has established communication with the master device and the communication destination; the slave out-side communication unit setting unit sets the value of the communication parameter to equal the stored value; and the slave out-side communication unit setting unit sets, if the slave device cannot establish communication in a predetermined amount of time and the value of the communication parameter is equal to the stored values, the values of the communication parameter to a value different from the stored value.

8. The network system according to claim 7 , wherein the communication parameter is at least one of a port type, a communication speed, and a full-duplex/half-duplex mode.

9. The network system according to claim 8 , wherein the slave out-side communication unit comprises a plurality of slave out-side communication units; the stored value comprises a plurality of stored values; and the communication destination comprises a plurality of communication destinations, each connected to a different slave out-side communication unit.